Research On Ultra-low Emissions Renovation Scheme Of 660 MW Circulating Fluidized Bed Boiler Dust

In the 21st century,the issue of environmental protection has gradually become the focus and focus of attention of the whole society.Effectively reducing smoke and dust content in coal-fired power plants has become a common consensus among national environmental protection regulatory agencies,environmental protection and thermal power industry practitioners.In December 2015,the Ministry of Environmental Protection issued the Notice of the“Full Implementation of the Work Plan for Ultra-Low Emissions and Energy-Saving Renovation of Coal-fired Power Plants”.The document states that the concentrations of sulfur dioxide,nitrogen oxides,and soot emitted(standard oxygen content 6%)do not exceed the limit values of 35 mg/Nm~3,50 mg/Nm~3,and 10 mg/Nm~3,respectively.This article takes a 660 MW circulating fluidized bed boiler in Shanxi Province as the research object.In order to meet the requirements of the ultra-low emission standards for the dust emission concentration of the boiler,the original dedusting technology system must be improved.Based on the study and investigation of the mainstream domestic dust removal process equipment and the ultra-low emission process route for the same type of boiler smoke,combined with the features of high ash,high sulfur,and low calorific value of the coal-fired unit of the project,the comparison and selection are suitable for this project.Ultra-low smoke emission process route and equipment selection.In the case that the original electric bag dust collector remains unchanged,it is proposed to increase collaborative dust removal process equipment and propose three reform programs.Solution one:Add an efficient dedusting demister(tube dedusting demister)at the top of the absorption tower;Option 2:Use an effective space between the absorption tower and the chimney to add a wet electrostatic precipitator;Option 3:Wet desulfurization(with tubing Dust eliminator)+wet electrostatic precipitator solution.Based on technical and economical comparisons,a retrofit plan was drawn up,and through the analysis of the operational data of the three research power plants,the final smoke and dust ultra-low emission retrofit program was determined as follows:electric bag dust collector+wet desulfurization(pipe dust removal demister)+wet Electrostatic precipitator.Analyze and compare the soot and dust parameters of the three research power plant units.The integrated dust removal efficiency at the end of the desulfurization and wet process(including pipe dust collector and demister)+wet and dry dust removal program is approximately 91%to 95%.The desulfurization wet method(with efficient tube bundles)The dedusting efficiency of the dedusting demister is approximately 88%to 90%.This example and the performance parameters of the dedusting equipment of the project can be used to judge that the integrated dedusting efficiency of the end of the boiler unit can reach more than90%.And according to the general absorption tower 50%dedusting effect,and 70%dust removal efficiency of the wet electrostatic precipitator comprehensive judgment,the conventional experience guarantees that the calculated efficiency is about 85%,whether based on the experience of dust removal effect analysis,or the actual dust removal effect of the same type of dust removal process,The ultra-low-emission reformation process plan of the660 MW circulating fluidized bed boiler in this project can achieve the desired goal.At the same time,according to the problems and information feedback during the operation of the dust removal process system,the optimization proposal for the operation of the dust removal system is proposed.